1. Technical Field of the Invention
The present invention relates generally to means for extending the battery life of portable electronic devices such as cellular telephones, and more particularly, to a switch capable of sensing the presence of an auxiliary battery and switching the power circuitry of the electronic device to the auxiliary battery.
2. Description of Related Art
The battery pack is the main power source for portable electronic devices such as cellular phones. The portable nature of cellular phones are limited by the fact that their battery power will not last forever. After a period of time the batteries become discharged and the cellular phone must be plugged into a charger in order to recharge the battery. In order to achieve more battery power (longer battery life), typically the size of the battery cell must be increased. This presents a problem for cellular telephone designers due to the conflicts between a desire for longer talk time and standby for the phone (i.e., longer battery life) and the desire for smaller, lighter telephones.
Existing solutions for the problems of shortened talk time and standby have been limited to the development of high capacity batteries for cellular telephone units. These batteries suffer from the limitations of size and weight mentioned previously. The conflict between size and power is made worse by the development of next generation telephones which are becoming smaller and smaller. Other solutions involve the use of improved battery technologies that increase the charge per volume and charge per weight ratios of existing battery systems. However, these improvements have not been sufficient to keep up with the smaller sizes of cellular telephone units that are possible using existing components and technologies. Thus, what is necessary for meeting the presently existing market needs is a means for increasing a cellular telephone's battery life while at the same time leaving the size and weight of the cellular telephone unchanged.